1. Field of the Invention
The present invention relates to a marine vessel power supply system that supplies power to a plurality of propulsion devices provided with engines, and to a marine vessel propulsion system and a marine vessel that use the marine vessel power supply system.
2. Description of the Related Art
An exemplary propulsion device for a marine vessel is an outboard motor. The outboard motor is, for example, attached to a stern of a hull. The outboard motor is a device with which a propulsive force is obtained by rotation of a propeller drove by a power of an engine. A plurality of outboard motors may be attached to the hull in accordance with the required propulsive force. The outboard motor includes an outboard motor ECU (electronic control unit) for output control of the engine, etc.
A steering apparatus, a remote control apparatus for adjusting the output of the outboard motor, and a gauge (meter) for displaying a state of the outboard motor are disposed at a marine vessel maneuvering compartment of the marine vessel. The steering apparatus includes, for example, a steering wheel or handle. Operation of the steering wheel or handle is transmitted by a cable to the outboard motor to enable the direction of the outboard motor to be changed. The remote control apparatus has a lever for shift position selection and engine output adjustment of the outboard motor. Operation of the lever is transmitted to the outboard motor via a cable. Shift positions include a forward drive position, a neutral position, and a reverse drive position. When the forward drive position is selected, a propeller rotation direction is set to the rotation direction that provides the propulsive force in the forward drive direction to the marine vessel. When the reverse drive position is selected, the propeller rotation direction is set to the rotation direction that provides the propulsive force in the reverse drive direction to the marine vessel. At the neutral position, the output of the engine is not transmitted to the propeller. The gauge includes a liquid crystal display unit, etc., and displays an operation state of the outboard motor, the engine output (rotation speed), etc. When a plurality of outboard motors are provided, a plurality of gauges are provided accordingly and displays are performed in correspondence to the respective outboard motors.
A local area network (inboard LAN) is constructed inside the marine vessel. The outboard motor ECU and the gauge are connected to the inboard LAN and data communication between these components is thereby enabled.
One battery preferably is provided for each outboard motor. Power is supplied to a starter for starting the engine and to the outboard motor ECU from this battery. The marine vessel maneuvering compartment includes a power supply switch for switching between supplying and turning off the power from the battery to the outboard motor. When a plurality of outboard motors are provided, a plurality of power supply switches are provided accordingly (see US 2006/0089060). The power supply switch has, for example, a form of a key switch and serves as a start switch for starting the engine as well. More specifically, when the key switch is operated from an off position to an on position, power is supplied from the battery to the outboard motor. When the key switch is operated further from the on position to the start position, the starter is actuated and a cranking operation is performed.